Answer:
Both the companies should enter into swap .
That means Dell would borrow dollar at 7% from market and give this loan to Virgin Airlines and similarly Virgin Airlines would borrow pound at 8.5% and give this loan to Dell .
In this way ,Dell would get desired pound loan at 8.5% and hence advantage or savings of 9-8.5=0.5%
Similarly,Virgin Airlines would get desired dollar loan at 7% hence advantage or savings of 8-7=1%